| 摘要 |
Microphone array for achieving a substantially frequency-independent directivity using a plurality of microphones disposed along a rectilinear array. The rectilinear array is at least as long as the wavelength of the lowest frequency, where a useful directivity is desired. The rectilinear array has a first end and a second end. The microphones close to the first end are intended for the highest frequencies and the microphones close to the second end are intended for the lowest frequencies. The mutual spacing of the microphones is frequency-dependent. The signals from the individual microphones are band-pass filtered, the passbands and cut-off frequencies of the individual band-pass filters being adapted to the frequency band the individual microphones are intended for. The individual band-pass filters are adapted such that the amplitude of the summated signal after band-pass filtering is substantially the same when a sinus-shaped test signal is used, the amplitude of said test signal being constant and the frequency of said test signal varying within the frequency range where the microphone array is to have a substantially frequency-independent directivity.
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